As the demand from users for bandwidth rapidly increases, optical transmission systems, where subscriber traffic is transmitted using optical networks, are being installed to serve this demand. These networks are typically referred to as fiber-to-the-curb (FTTC), fiber-to-the-building (FTTB), fiber-to-the-premise (FTTP), or fiber-to-the-home (FTTH). Each such network provides access from a central office (CO) to a building, or a home, via, e.g., optical fibers installed near or up to the subscribers' locations.
Examples of optical transmission systems include passive optical network (PON), such a Gigabit PON (GPON), an Ethernet PON (EPON), and Active Ethernet. An Active Ethernet is a type of a FTTP network that uses optical Ethernet switches to distribute the signal, thus incorporating the customers' premises and the central office into a switched Ethernet network.
An exemplary diagram of a typical PON 100 is schematically shown in FIG. 1. The PON 100 includes M optical network units (ONUs) 120-1 through 120-M, coupled to an optical line terminal (OLT) 130 via a passive optical splitter 140. Traffic data transmission may be achieved by using two optical wavelengths, one for the downstream direction and another for the upstream direction. Downstream transmission from the OLT 130 is broadcast to all ONUs 120. Each ONU 120 filters its respective data according to, for example, pre-assigned labels. ONUs 120 transmit respective data to OLT 130 during different time slots allocated by OLT 130 for each ONU 120. Splitter 140 splits a single line into multiple lines, for example, into lines 1 to 32, or, in the case of a longer distance from OLT 130 to ONUs 120, into lines 1 to 16.
The GPON, EPON or Active Ethernet systems are currently being adopted by many telecommunication companies in order to deliver high-speed data services to their subscribers. These services typically include a bundle of TV broadcasting, Internet, and telephone services.
To provide these services an ONU 120 is connected to a residential gateway installed in the premises. As illustrated in FIG. 2 an input of a residential gateway 210 is connected to the ONU 120. The gateway's 210 outputs are coupled to, for example, a telephone device 220, a TV set-top box 230, and a computer 240 to provide Internet connectivity. Generally, a residential gateway may provide the functionality of a modem and router and may be, for example, a cable modem, a router, a switch, a wireless modem, a wireless router, and so on.
Specifically, network units, such as ONUs are equipped with a network processor (e.g., PON processor) utilized to receive the downstream traffic from a terminal unit (e.g., an OLT), and provide the contents of the downstream traffic to one or more subscriber devices, i.e., devices connected to the gateway 210. Similarly, the network processor is designed to receive and transmit upstream data from the one or more subscriber devices to the terminal unit via the network, e.g., the passive optical network.
Because residential gateways are required to support advanced applications and to process high volumes of traffic, the currently available network processor, and especially PON processors, have become bottlenecks which limit the performance of residential gateways. For example, such processors cannot efficiently support security applications, such as firewalls, attacks prevention, and IP security (IPSEC) protocol, while performing the traditional networking processing tasks of switching and bridging.
Therefore, it would be advantageous to provide a network processor that supports the processing requirements of residential gateways.